Computer graphics has always been a valuable tool to study scientific problems. In the past, however, the lack of graphics power limited its usefulness. The recent emphasis on visualization started around 1987 when high end computer graphics first became available. Today, the advent of volume visualization not only enables the geoscientist to see and work with their data in its natural 3-D form, it also brings a new level of understanding. Visualization provides the medium and opportunity to integrate technologies such that the greatest amount of information can be accurately, efficiently, and economically obtained in the search for hydrocarbons, if properly used.
There are many techniques for displaying various data types. Line charts can be used to represent 1-D scalar data, and scatter plots or 2-D contours can be used to image 2-D data. For 3-D images, structure fields or 2-D contours over planar slices can be used, or 3-D can be represented using isosurfaces. Traditionally, the visualization of three-dimensional data has been accomplished using geometric models, due to limitations in available compute power. This polygonal geometry rendering technology has been around for over a decade, and was designed specifically to provide interactive imagery of geometric constructs created on a computer, such as a wireframe CAD surface model. The images generated by these techniques were based on models that consisted of geometrically described surfaces oriented in 3-D space.
Volume rendering, however, allows the display of information throughout a regularly gridded 3-D space. The basic idea in volume rendering is to cast rays from screen pixel positions through the data, obtain the desired information along the ray, and then display this information in a format meaningful to the computer users (i.e., colors). The data visualized can be an average of the data in a cell ("voxel"), or of all cells intersected by the ray (i.e., optical stacking), or some other such measure computed for various orientations and parameter settings.
The traditional way to interpret three-dimensional seismic data cubes was by viewing a series of 2-D images ("slices"), digitizing them, and making 3-D structural maps. Given today's pressure on timeliness and cost-effective outcomes, 3-D volume imaging is an extremely valuable exploration tool for accelerating the seismic interpretation processes and eliminating uncertainty in structural and stratigraphic features; thus obtaining better insight needed to make informed drill location decisions promptly.